Date: Fri, 5 Dec 1997 15:57:29 +0100 (CET) From: pb@fasterix.frmug.org To: FreeBSD-gnats-submit@FreeBSD.ORG Subject: kern/5236: CPU and mem not zeroed for zombie process Message-ID: <199712051457.PAA04190@ns.eu.org> Resent-Message-ID: <199712051500.HAA02390@hub.freebsd.org>
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>Number: 5236
>Category: kern
>Synopsis: CPU and mem not zeroed for zombie process
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Dec 5 07:00:03 PST 1997
>Last-Modified:
>Originator: Pierre Beyssac
>Organization:
none
>Release: FreeBSD 2.2.5-RELEASE i386
>Environment:
486DX50, 8 megs RAM.
>Description:
ps shows zombie processes left with non-zero %CPU and %MEM:
bash$ ps axuww
USER PID %CPU %MEM VSZ RSS TT STAT STARTED TIME COMMAND
pb 4076 78.4 0.1 0 0 p1 Z - 0:00.00 (a.out)
...
The values stay stable while the zombie is in the process table.
>How-To-Repeat:
Compile the following code (trivial: forks, then the child uses
the CPU while the parent waits 10 minutes):
-------------------------------
#include <stdio.h>
int main()
{
switch(fork()) {
case -1:
perror("fork");
return 1;
case 0:
/* in child */
for(;;);
exit(0);
default:
/* in parent */
sleep(600);
}
return 0;
}
-------------------------------
Run it:
$ ./a.out &
[1] 4075
Wait for the child to show-up with a reasonnable %CPU:
$ ps axuww | grep a.out
pb 4076 82.2 6.3 136 400 p1 R 3:46PM 0:05.60 ./a.out
pb 4075 0.0 6.4 136 404 p1 S 3:46PM 0:00.04 ./a.out
Kill the child:
$ kill 4076
Look at ps again:
pb 4076 78.4 0.1 0 0 p1 Z - 0:00.00 (a.out)
pb 4075 0.0 0.0 136 0 p1 SW 3:46PM 0:00.04 ./a.out
>Fix:
>Audit-Trail:
>Unformatted:
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